In the right window of Fig. REF  the kinetic energy dependence of the single-nucleon potential \(U_0(\rho _0,\mathbf {k})\)  is shown, with the corresponding kinetic energy defined as \(E_{\mathrm {kin}}=[\mathbf {k}^2+M^2]^{1/2}+U_0(\rho _0,\mathbf {k})-M\)  [1]}, [2]}.
Also shown is the experimental constraint on the single-nucleon potential obtained from the optical model analysis of nucleon-nucleus scattering data [3]}.
Since the \(\alpha +\beta +\lambda +\phi \)  in the two parameter sets are the same, i.e., about 62.8 MeV, it is unnecessary to distinguish the two parameter sets.
Although the momentum dependence of the \(U_0(\rho _0,\mathbf {k})\)  is very simple it can successfully model the constraint from the optical model analyses.
Similarly shown in Fig. REF  is the density dependence of the single-nucleon potential at different momentum.
As the density increases the \(U_0(\rho ,k)\)  eventually increases from negative values to positive at the crossing density \(\rho _+\) .
The crossing density \(\rho _+\)  itself decreases as the momentum increases, i.e., in a system with high-momentum nucleons the effective interaction between nucleons starts to be repulsive earlier than a system with low-momentum particles as density increases.
The crossing density \(\rho _+\)  is obtained as follows,
\(\alpha \left(\frac{\rho _+}{\rho _0}\right)+\beta \left(\frac{\rho _+}{\rho _0}\right)^{4/3}+\lambda \left(\frac{\rho _+}{\rho _0}\right)^{5/3}+\phi \left(\frac{\rho _+}{\rho _0}\right)^2+\mu \left(\frac{\rho _+}{\rho _0}\right)\left\bad.\left(1+\frac{\theta |\mathbf {k}|^3}{\Lambda ^3}\right)\right.=0.\) 
